Process for manufacturing ammonium carbonate and sulfur from crude coal-gas.



H.L.DOHERTY. PROCESS FOR MANUFACTURING AMMONIUM CARBONATE AND SULFUR PROM CRUDE GOAL GAS.

APPLIG ATION FILEDIEB. 15, 1910.

- Patented Nov. 5, 1912 3 SHEETSSHEET l.

Henry L. Duherty, ammwtoz 'H. L. DOHERTY. PROCESS FOR MANUFAGTURING AMMONIUM GARBONATE AND SULFUR FROM CRUDE GOAL GAS.

APPLIGATION FILED 1155.15, 1910. 1,043,,Q12.

Patented Nov. 5, 1912.

s SHEETS-SHEET 2.

H. L. DOHERTY. v PROCESS FOR MANUPAGTUBTNG AMMONIUM OARBONATE AND SULFUR FROM ORUDE GOAL GAS. APPLICATION IILED FE]3.15, 1910.

1,048,212, Patented N015, 1912 3 SHEBTSSHEET 3v mm: v Henry LBuherty, wvewto'e a. n a/ttomwgww print s'rnrnis an anion.

HENRY L. DOHERTY, OF NEW YORK, N. Y.

PROCESS FOR MANUFACTURING AMMONI UM CARBONATE AND SULFUR FROM CRUDE COAL-GAS.

Patented Nov. 5. l 912.

Application filed February 15, 1910. Serial No. 544,096.

T 0 all whom it may concern:

Be it known that I, HENRY L. Donnu'rY, a Citizen of the United States, and a resident of New York city, in the county of New York and State of New York, have invented certain he and useful Improvements in Processes for ltlanufacturing Ann monium Carbonate and Sulfur from Crude Coal-Gas, of which the following is a specification.

My invention relates to a process for manufacturing ammonium carbonate and sulfur from crude coal gas.

The object of my invention is to provide a process whereby the ammonia of the crude gas may be recovered as carbonate in com bination with the C0,. of the gas and the sulfur of the crude gas recovered in the free condition.

In the usual manner. of fixing the ammonia formed in the distillation or gasifi cation of coal, the ammonia-bearing gases are conducted through a suitable chamber in which they are contacted with sepa'ately manufactured sulfuri' acid, fixing the ammonia as mmonium sulfate. This product is used as the source of ammonia for various industrial purposes but, chiefly, as a fer tilizer. By my method, I am able to fix the ammonia in a form more readily available for industrial use,and which is equally available as a fertilizer, without. the necessity of using any chemical reagents other than those obtained from the coal at the same time as the ammonia.

Br efly, my .lIlVGIltlOIl consists m absorbmg the ammonia, carbou-dloxid, and hydrogen sulfid of the distillation gas in a partially purified ammonia liquor, containing a substantial proportion of its ammonia in the free or hydrated condition, separately separating the ammonia, on the one hand, and the carbon-dioxid and hydrogen sulfid, on the other from said liquor, passing the mixed acid gases through a bed of iron oxid, together with suflicientair to liberate the sulfur of the hydrogen sulfid as free sulfur, separating out the free sulfur from the residual gases, which contain the CO, unchanged, mixing the residual gases with the separated ammonia. and recovering the ammonia carbonates formed.

. In .my-co-pendingapplications Ser. Nos. 544,094 and 544,095, I have shown and claimed processes more or less closely allied to the one herein revealed.

in the accompanying drawings, 1' have shown, in diagrammatic form, an arrangement of apparatus suitable for applying my invention.

Figure 1 is a perspective view of the gas washing and cooling apparatus. Fig. 2 is a detail of the same showing how the scrubbing liquor passes from compartment to compartment of said apparatus. Fig. 3 is a diagrammatic elevation of the apparatus for separating the ammonia and, the'carbon dioxid and hydrogen sultid from the scrubbing liquor'andrecovering the ammonium carbonate and free sulfur, therefrom. .Fig. 4 is a detail of the still shown in Fig. 3. Fig. 5 is a section of the upper boiling compartment of the still. Fig. G-is a Vertical diametral section through the cooler and sepa- -ator of the ammonium salts on the line A B of Fig. 7. Fig. 7 is a horizontal crosssection. of the cooler-separator on the line C D of Fig. 6. Fig. 8 is a top view of the cooler-separator; while Fig. 9 shows a partial development on a vertical plane of one of the walls of the spiral partition of the cooler-separator with the bafiles, which guide the flow of the coolingliquid,attached.

. Fig. 10 shows an auxiliary condenser.

In the drawings, 1 is the absorption apparatus or gas washer. This is divided into a plurality of compartmentsa, b, 0, d, e, f, g, and I2, in the-design shown, each compartment having located above it a compartment (2,, 2 2 etc., respectively) in which isa cooling coil (3,, 3 etc), through which the liquid used in the compartment to wash the gas is passed, for the-purpose of cooling it, beforeintroducing it into the Washing compartment in contact with the gas. The cooling is performed, in the apparatus shown, by the circulation of a cooling liquid around the coils in the compartments 2. Circulating pumps, 4,, 4 etc, maintain a constant circulation of liquid from the bottoms of the compartments to the respective device which should secure a uniform diam- 1 bution of the liquid across the orosssection of the c up-nitmeat. lhe:-'e mmpartments, a, t), 0, etc, generally c ntain a structure of grids or trays over the surlace o'l, which the liquid finds its my to the bottoms of the compartments. The surface of the grids (or whatever term of lllllllf" is used) is thus kept continually \vetted. the gas passes through the inter.-;tic-s ot' the grid structure and is thus brought into intimate contact with the scrubbing liquid. The gas enters through the gas inlet 9-! and pas es through all of the compartments (1, r), c, (1, etc, in series,linally discharging from compartn'ient /1. through the outlet 97.

In compartment /L, the gas, which here should contain onlya trace of NH,, and the acid IE3 and CO is subjected to Scrubbing by a portion of previously it'orn ed ammonia liquor, which has been freed, in

the manner hereinafter described, from substantially all of its volatilizable compounds. The extent to which it is necessary to remove the volatilizable gases t'rom this portion ol the liquor depends, in great measure, upon the temperature that prevails in it.

ammonia has a considerable atlinit for voter, even weal; solutions of NIL, in water possess an appreciable vapor tension at ordinary temperatures. It is necessary that the liquor used for scrubbing in /i. should have a vapor tension of its ,Nll less than the tension of the small quantity of NFL, in the gas passing through compartintuit/1. 'Usually, the linal traces of NH, are removed from the fresh ater. 3y my method, however, I prefer to use the liquor that has been freed from its volatiiizable ammonia in order to avoid the dilution ol the liquor that is occasioned by the use of fresh water. The liquor in it is maintained in circulation by pump l as already explained. A portion of this liquor, corresponding to the volume of :l'resh liquor introduced through pipe 7, overflows to compartmcnt through the sealing device shown in Fig. and mixes with the liquor circulating in compartment 7. This sealing device is tormed by two battles, 8 and 8,, respectively, spaced some distance away from the vertical sheet separating the chambers. Near the bottom of this sheet are numerous apertures, Normally,-the level of the liquor in the chambers is maintained at a d pth sonuivvhat greater than the height of the battles. As the liquor is withdrawn from tin-system (:t'rom compartment (Z as shown) the level in (I tends to fall. This causes a flow 01. liquor from c to (Z through the apertures in the dividing wall, which in turn causes a How from the next compartment, and so on. The liquor seals between the compartments are all similar to the one shown as connecting compartments and h. The liquor is introduced to g by the pipe 9 gas by scrubbing with connected. in the arrangement shown, to the suction pipe 5, of pump t and is circulated in the manner described, a volume of liquor corresponding to the overflow from 72' and the quantity of purified liquor introduced through 1) (plus the condensation from the gas overflows to compartn'ient f. The liquor (lows in this way from compartment to compartment, a volume being maintained in circulation in eachcompartment much greater than the volume of the tlow from compartmentto conipartmei'it. The volume of liquor supplied. through the pipes 7 and. 9

tl(.[')ll(lS, in great measure, upon ts content of ammonia. in the liquor supplied by the pipe 5) the quantity oflree ammonia that will sullice, in connection with. the ammonia already present ii: the gas, to form sultid and carbonate, .respectively, with the ll syand CO the 'udc gas. When the proper quantity of treeammonia is supplied in the liquor sub stantially all of the l-l S, CO. and. NIL, may be removed from the crude gas. In my preferred method of working, I withdraw the liquor vbearing the H 55, CO -and NIL, from compartment. (Z through pipe 10 and run it to the ammonia-sulfur recovery plant. This is shown diagrannnatically in Fig. 3.

ll, is the still in which the impurities removed-from the gas are separated from the liquor, and about half of the ammonia in the latter again converted to the tree or hydrated condition. 11 has, in its lower portion, three boiling chambers, 19, 13 and 14. l pon the uppermost; of these boiling chambers, 1:2, is built up the still proper. This is composed of a plurality of sections, 15, 15 15", etc, arranged as shown in Fig. 4t. 16 is a heater-cooler or heat inter-changer, consisting of a cylindrical tank having an upperv and lower tube-sheet (l7 and 18, respectively) with tubes supported thereby. The chamber included between the tube sheets is divided by partition 19 into two compartments, 1 6 and '10. The liquor passing through pipe 10, which contains the NH [LS and (70, absorbed from the gas, enters 16 below the tube sheet 18,, and passes up througl'i the tubes (not shown) to the space above the upper tube-sheet, 17. During its upward passage through the tubes,

-t'ho liquor is'heated by two streams of hot It is necessary to introduce,

liquor passing in the contrary direction thrraigh the compartments l6- and 16-. The gases evolved from the liquor, inthe course of this heating discharge from 16 through the pipe 20 into one of the sections (15 as shown) of Still 11. The heated liquor from 16 passes through the pipe 20 and enters one. of the sections, (15*, as shown). From 15* it overflows from section to section through the sealed overflow-passages '21, into the upper boiling compartment 12. As the liquor passes through the sections 15, it is subjected to the action of the hot gases discharging from the compartment 12. Now the'ammonia sulfid of the liquor begins to dissociate at about 98 Fah., while the ammonium Carbonate dissociates at'about 124 Fah. A portion of these gases is therefore evolved from the liquor, even during its passage through 16. During its descent to the boiling chamber 12, the hot gases from 12, which bubble through it, eliminate some more of the H S and CO, from the liquor, at the same time that they give up the larger portion of the i l-1,. which they carry, to the liquor, since the atiinity of the NH for the water is much stronger than that of the other gases mentioned. In the heating chamber 12, the liquor is heated to a temperature of from 196 to 206 Fah. by means ofthc,steam coil 22. The temperature maintained in 12 depends upon the temperature of boiling corresponding to the pressure. conditions in compartment 12. This depends, of course, upon the altitude of the locality in which the treatment is carried outand upon the back pressure caused by the liquid seals in the compartment. I aim to carry on the distilling oper: ation in 12 at a temperature varying from 6 to 12 degrees below the boiling point of water under the pressure prevailing in 12. For example, if the barouietic pressure in 12 is about 25.9 inches of mercury, I would, preferably, maintain the temperature in 12 at about 197 to 198 Faln, while at a barometic pressure of say 31.3 inches in 12, I would, preferably, heat the liquor, therein, at a temperature of about 204 to 206 Fah. At this temperature there is a very rapid dissociation of the ammonium sulfid and carbonate. The liberated H 3 and (.0 are immediately evolved while the greater part of the free ammonia formed is retained in the liquor owing to the relatively great absorption coeiiicient of water for ammonia at even the temperature prevailing in 12. The liquor discharging. from 12 is divided into two streams. The main stream passes through the overflow 12 into the section 15. Here it has passed through it any excess of ammonia (and its accompanying gases) that is driven off from the liquor in the boiling compartments or rctorts 13 and 1.4,ovcr that portion withdrawn from 13 through the pipe 32. The gases from 13 and 14 are relatively strong in ammonia and the passage. of a portion of them through this purified liquor strengthens it and increases its purity. The portion of the gases evolved in 13 and 14 which passes through 15, passes up through 'the vapor passage 57 in the bottom of 15 under the hood 58,

depresses the liquor level under 58 until the perforations 50 are unsealed, up through the v perforations 59 and, bubbles through the flow 12 36 and 37211111 the partially purified liquor in 15, thence, the unabsorbed gases, pass in a similar manner throughthe liquor in 12, and on up through the sect-ions 15 15 etc. The temperature of this liquor in 15 being only about 19S'to 203 degrees Fah. a portion of the ammonia in the gases from 13 is absorbed by the purified liquor, bringing the latter to nearly the saturated condition at this temperature. Since this temperature is far above the dissociation temperature of the suliid and carbonate of ammonia, and the. solubility co eiiicients of the ILS and (.0 are practically in! at this temperature, there is practically no'contamination ot' the liquor in 15 by these gases. The liquor, after passing through 12 and 15, will have had about 50 to (30% of its riginal ll. ..S and (O eliminated with? a loss of only about 3% of its ammonia. 'Ihe'residual ammonia is present free, or hydrated ammonia to the extent of about 50 to 60 per cent. of the total. By decreasing the velocity oi flow it. is possible to increase this proportion of free ammonia but, at the expense of the production of a weaker liquor. "Jhere'lore, I have found that the method ofworking outlined gives the most economical results.

FronrlS. the main stream of purified liquor is withdrawn through the pipe 23 and is forced by pump 24- to the top ofvcompartment 10 of heater-cooler 10. The other st ream is permitted to pass through the overin quantity regulated by valve 12,, into the boiling compartment, or retort, 13.

whereby substantially all of'the remaining sulhd and carbonate of ammonia is decomposed with the evolution of the ammonia and hydrogen sulfid and carbon dioxid. The ammonia and steam from the liming com 'iarlmrnt or retort 14 joins and mixes with the gases evolved in 13. Since the gaseous current from 14 is con'iposed almost entirely of ammonia and water vapor, while the ammonia constitutes nearly one-half of the fixed gases evolved in 13, the gasesjfrom these two compartments, after condensation, are very strong in ammonia. Therefore, I prefer to remove from the system its increment. in ammonia, at this point. I withdraw from 13, through the pipe 32, the proportion of its vapors which carry aquan-' .llere it is subjected "to active ebullition, w

tity of ammonia corresponding to the ammonia increment of the system, and lead them to the purifiers 36 and 37, which are charged, respectively, with iron oxid and lime. The pipe 32 should be long enough to cool the gases and condense the water vapor present, the condensed liquid being returned to the con'ipartment 13, through the pipe 32, by gravity; or a cooling coil (not shown) may be introduced on 32 between 13 and 36.

The gases from 32 pass through the purifiers hydrogen sulfid' and carmanner to the top section.

bon dioxid are here separated from the ammonia. The pure ammonia passes through the pipe I) and joins the treated ellluent gases trom the till l1v in the condensing ap paratus 41s. The remainder of the vapors generated in 11% and ti pass up through l5, l9. 15. etc, as above de cribed. These sections are shown in ver .-'al cross-section in Figs. -l and 5. The gases from t5 pass up through the vapor passage 0 in the bottom o. l"). under the hood til through the perforations 3), bubbling up through the liquor in 1;. where a t'urther portion oi. the NH, of this current is absorbed. thence, with the gases erolred in 12, through thevapor passage (1:3 and perforations (35 of hood (it bubbling through the liquor in 15, thence through the sections l5, 15, etc. in the same These sections 15', ete., are alike in construction. The gases enter ("ttt'lt st't'iiml in turmtln'ough the projecting vapor passage (13 in its bottom passing under the hood tit and through perforations ti?) and into the next section above, as already described. 'lheliquor finds its way down from sertiiin to section through the overtlows 2t.

The. boiled liquor discharging from 13 is suhdhided into two streams, one being drawn oil through the pipe and raised by pump 21? tothe top ol lwater-cooler com- 'mrtment us. The other subdivision of the liquor passes through the overtlow 27 into the liming 'ctnupartment let. The liquor leaving it) contains only the tixed salts of ananoni: -sulfate. ehl'u'id, etc. The proper (piantit-y ot mill; of lim is run into 14, through the pipe 2am eomhiue with the acid ot' the, tixed ammonium salts and liberate the Nll 'lhis passes up through the pipe 29 into the vaporspaee of i3, and joins the gaseous current discharging from '13. The liquor discharging from 14., which has been freed from all' of its ammonia, both volatile and fixed, is permitted to run to 'aste through the waste pipe 83. i

The cooled liquor discharging from com partn'ient 16 is divided into two streams. One of these, streams-passes directly to the circulatin pinup ot' compartment /L-l'l1l'0tt ;lt the pipe t. while the smaller stream is con ducted to the uppermost section (15 as shown) of the still it. through the pipe 3! and cooling coil ll ()vertlowdng from tfi" through the sealed overtlmv passage, it passes into the section 15 and thence dowuward through the ditl'erent sections. until it joins the main stream of foul liquor. entering through the pipe .50. The unabsorbed gases from 12 and those evolved from the foul liquor are thus contacted with a liquor which. at its (l-tlt';lll('( to It. is substantially .tree from volatile ammonial This liquor removes from the gases passing througlrll thetinabtraces of their ammonia, and also I. I i l .and the air admitted through 43, are forced by fan 39 below the grate 12 of the oxid chamber 1-0. On the grate-of 40 is a bed of oxid of iron, 41, or some similar reacting material. This must be raised initially to low redness; but. after the react-ion has been startml. the heat developed is sutlicient to maintain the temperature of the oXid. The net reaction which takes place in the oxidizing chamber may be represented thus,

With the proper proportion of H s and O in the gas mixture this reaction takes place. in contact with iron oxid at a red heat almost completely. The actual process which takes place is not according to the equation given, however. The l'l S is first decomposed with the formation of water vapor and iron sulfid. The latter is immediately oxidized again by the oxygen present to oxid which, in turn, reacts with a fresh portion of ILS, the S being liberated as frees. The oxid of iron thus passes through a cycle or, in other words, acts simply as a catalytic agent. Any material which will fulfil the same otlice such as platinized asbestos may be substituted for the oxid of iron, if preferred. The CO of the mixture is unchanged. The proportion of air that should be added is thatwhieh will supply a volume of oxygen equal to about one-half of the normal volume of the ILS. The gas miX- ture, after passing through t1, consists, chiefly, of nitrogen. carbon dioxid, sulfur vapor, and steam. with a smalt proportion of 110 sulfur dioxid. The gases are led througlr" the conduit :44 to the sulfurcondensing chambers 4-5. These may be built of concrete or masonry, and their function is simply to cool the gases from 40 sufl'icient-ly to 115 I solidify the sulfur vapor and reduce the velocity of the gases sufficiently to permit the sulfur to settle out. If preferred, a centritugal separator may be substituted for 45. It is only necessary that some device be 120 used which will, insure the separation of the sult'ur vapor from the gas mixture. From 11-? the gases freed from their sulfur pass to tln ammonium carbonate condenser 46.

Here the gases, which now consist chiefly of 125 carbon dioxid nitrogen and steam, are'mixed with the purified ammonia discharging from the pipe 38. In passing through the ammonium carbonate condenser the gases are reduced to at least 100 F all. Under the 130 cry of 46 to the axial conditions obtaining in the condenser 46 the ammonia and water combine with part of the excess of CO," present reform the socalled sesquicarhonate of ammonia. This cryst-allizes'on the walls of the condenser and may be scraped off by means of suitable rabbles introduced through the openings .47, and withdrawn from 46 through the discharge openings 48 in the bottom of the same. A layer of carbonate, sufficiently deep to seal the bottom of the spiralpartition 49 should be maintained in 46 to prevent the passage of the gas from the periphpassage of the same, under the partition 49.

The ammonium carbonate condenser con- 'sists, simply of a spiral gas passage, 50,

'formed by the hollow spiral wall 49. The

. monia carbonate gases enter at the peripheral inlet 51 and discharge froml the axial passage 53. Water circulates through the spiral passage 54 in wall 49, entering at and discharging from 56. Battles 66, shown in Fig. 9, force the 'vvater to flow through 54 in a vertical serpentine course, thus insuring that the cooling of the gas takes place with a fair degree of uniformity from the periphery to the axial discharge of 50.

I have found that in recovering the carbonated ammonium salt from an excessive volume of diluent gases, it is very difficult to secure a perfect recovery of the ammonium carbonate by dry condensation. Therefore I prefer to subject the effluent gases from the dry condenser 46 to wet condensa tion in the condenser 67. This, as shown, is an apparatus of a well known type, and any equivalent device. may be used instead of this. It consists of a number of superimposed sections, 68,'69, 70, 71,.etc. The section 68 is simply an open cylindrical chamher into which the gas is introduced and from which the saturated mother liquor circulated through 67 is withdrawn. The other sections each-have a bottom having a large opening, '73, over which is a perforated dome, 74:. 7% does not come into contact with'the bottom of the sectiombut there is a clear space between it and the bottom. The. gases bubble up through the liquor in the chambers, through the opening into the one above, throughthe dome-shaped .sheet 74, and finally discharge from 67 through the pipe 7 5. The cooled mother liquor enters 67 from the pipe 76 and gradually works down through 67, taking up any amin the gases passing through. The liquor being saturated, the

ammonia salt immediately crystallizes out.

The crystals Work down through 67, from section to section and are carried outpiziith the liquor from 68 through the pipe 77, and

discharged on the screen 78 of tank 79. The crystals are caught on the fine screen 78and may be removed at intervals. 'The liquor is drawn from 79 by the'circulating pump 80 and forced through the cooling coil 81 and pipe 76 into the top of 67. v

Having described my invention, what I claim is:

1. The process of treating crude gas to recover therefrom commercial ammonium carbonate and free sulfur which comprises separating ammonia, hydrogen sulfid and carbon dioxid from said gas, separating said hydrogen sulfid and carbon dioxid from said ammonia, converting the said hydrogen sulfid to water vapor and free sulfur, separating said free sulfur from residual gases containing water vapor and carbon dioxid, mixing the said separated ammonia with said residual gases to form ammonium carbonate and recovering said ammonium carbonate.

2. The process of making ammonium carbonate and free sulfur from gases containing 5 free ammonia, hydrogen sulfid and carbon dioxid which comprises separating sald constituents from said gases, separating hydrogen sulfid and carbon dioxid from said ammonia, mixing with said hydrogen sulfid and carbon dioxid sufiicient oxygen to oxidize the hydrogen of said hydrogen sulfid, subjecting the resulting mixture to reaction to form water and free sulfur, separating free sulfur from the residual gases of said mixture, mixing said residual gases with free ammonia to form an ammonium salt of carbonic acid, and recovering the said salt.

3. The process of making ammonium ar- 10o bonate and free sulfur from gases containing ammonia, hydrogen suhid and carbon dioxid which comprises separating said constituents from said gases, separating hydrogen sulfid and carbon dioxid from said am- 105 monia, mixing with the said separated hydrogen sulfid and carbon dioxid sufficient oxygen to oxidize the hydrogen of said hydrogen sulfid, subjecting the so-formed gas 'mixture to reaction to form water and free no sulfur, separating free sulfur from residual gases of said mixture containing carbon dioxid and water vapor, mixing said residual gases with the previously separated ammonia, cooling the resulting gaseous mixture containing carbon dioxid, water vapor and, ammonia to form a hydrated carbonated salt of ammonia. t

4. The process of making ammonium carbonate and free sulfur from gasesycontainin'g ammonia, carbon dioxid and hydrogen sulfid, which comprises separating said constituents from .said gases, separating said hydrogen sullid and carbon dioxid fromsaid ammonia, mixing vwith saidsepai'atfed hy- 12s drogen sulficl and carbon dioxid sufiicient oxygen to oxidize the hydrogen of said hy: drogen sulfid, contacting'the so-formedg'as mixture with catalytic material which is capable of causing the oxygen of said gas which comprises separating said separated ammonia mixture to combine with the hydrogen sul'tid of the same, with the formation of water and free sulfur, separating the free sult'ur from the residual gases of such gas mixture, mixing the said residual gases with the said separated ammonia and recovering the carbonate of ammonia formed.

5. The process of making carbonate of ammonia and tree sulfur from gases containing ammonia, carbon dioxid and hydrogen sultid said constituents from said gases, separating the said hydrogen sulfid and carbon dioxid from said am monia, mixing the said separated hydrogen sultid and carbon dioxid with sutlieient air to furnish enough oxygento oxidize the hydrogen of said hydrogen suliid, suliijecting the so-tormed gas mixture to treatment which will cause the oxygen of the mixture to unite with the hydrogen of said hydrogen sultid, thereby liberating the sulfur 01 the same, removing the liberated sulfur from the residual gases of said gas mixture, mixing the said residual gases with the said separated ammonia, maintaining the temperature of the resulting mixture below the temperature of dissociation of ammonium sesquicarbonate, whereby the ammonia of said gas mixture combines with more or less of the water and carbon dioxid of the-same to form a carbonate of ammonia, and recovering said carbonate of ammonia from the residual gases ot' said gas mixture.

6. The process of making carbonate of ammonium and tree sultur from gases, containing ammonia, carbon dioxid and hydrogen sultid', which comprises separating said constituents from said gases, separating said hydrogei'i sultid and carbon dioxid from said ammonia, mixing with said separated hy-' drogen sultid and carbon dioxid sutl'icient oxygen to oxidize the hydrogen of the said hydrogen sultid, contacting the so-tormed gas mixture with a metallic oxid which is capable of acting to transfer the oxygen of said gas mixture to the hydrogenot said hy lrogen sultid with the liberation of the sulfur ot' the same, removing the separated sulfur from the residual gases of said mix ture, mixing the said residual gases with the and cooling the mixture so formed to a temperature below the dissociation temperature of ammonium sesquicarbonate, and separating the sotormed carbonate of ammonia from the residual gases.

7. The process of making carbonate of ammonia and tree sulfur from gases containing ammonia, carbon dioxid and hydrogen sultid, which comprises separating said constituents trom said gases. separating the said hydrogen sulfid and carbon dioxid from said an'unonia. mixing the said separated hydrogen sultid and carbon dioxid with sufficient oxygen to oxidize the hydrogen of said hydrogen sulfid, contacting the soforned gas mixture With oxid of iron at a temperature such that the oxygen of said gas mixture is caused to combine with the hydrogen of said. hydrogen sulfid with the liberation of the sulfur of the same, separating the so-liberated sulfur from the residual got said gas mixture, mixing the said residual gases with the said separated ammonia, cooling the so-formed gas mixture below the temperature of dissociation of car bonato of an'nnonium, whereby the ammonia of said mixture is caused to combine With more or less oi. the carbon dioxid and Water of the same to form a carbonate of amnionia, and recovering the same from the residual gases.

The process of making ammonium earbonate and tree sultur from gases containing ammonia, carbon dioxid and hydrogen sullid which comprises separating said constituents from said gases, separating said hydrogmi sulfid and carbon dioxid from said ammonia, mixing with gen sul'fid and carbon dioxid a proportion of oxygen approximately equal in weight to one-halt of the said hydrogen sultid, contacting the sieformetl mixture with catalytic material capable of causing the oxygen of said mixture to unite with the hydrogen of the hydrogen sulfid, liberating the sulfur of the same, sepa rating the so-liberated sulfur from the residual gases of said gas mixture, mixing the separated ammonia with said residual gases, reducing the resulting gas mixture to a temperature below 124 Fain, whereby the ammonia of the gas mixture combines with carbon dioxid and water of the mixture to form a carbonate of ammonia. and separating the so-t'ormed carbonate of ammonia from the residual gases I of said mixture! 9. The process of making ammonium carbonate and free sulfur, from gases containing ammonia, carbon dioxid and hydrogen sultid, which comprises separating said constituents from said gases, separating said hydrogen sulfid and carbon dioxid from said ammonia and mixing with the separated hydrogen sulfid proportion of oxygen approximately equal in weight to one-half of the said hydrogen sulfid, contacting the so-tormed mixture with oxid of iron at a t'eu'iperature such that the oxygen of the said mixture is caused to combine with the hydrogen of the said hydrogen sulfid liberating the sulfur of the same, separating the so-liberated sulfur from the residual gases of said mixture, mixing the said residual gases with the said separated an'unonia and reducing the temperature of the l ahi, whereby the said ammonia conibines with more or less of the carbon dioxid and water vapor of the same to form a carbon the separated hydro-' and carbon dioxid aresulting mixture below 124 constituents from said gases, separating the sald hydrogen sulfid from said ammonia,

mixture with a 'material capable of'causof the ammoniaare evolvied from said ,carbonate' and free sulfur from gases a proportion of oxygen approximately ammonia, reducing the temperature of said ate of ammonia, and separating the soformed carbonate of ammonia from the residual gases. V

10. The process ofmaking ammoniumcontaining ammonia and hydro-gen sulfid" WhlCll comprises separating the said mixing with said hydrogen sulfid sulficient oxygen to oxidize the hydrogen of the same, contacting the so-formed ing the oxygen of saidymixture to combine with thehydrogen of the hydrogen sulfid 1n the same, thereby liberating the sulfur of the same as free sulfur, recovering said free sulfur, mixing the said separated ammonia with carbon dioxid and vapor, reducing the temperature of i such mixture below 125 Fah. whereby the ammonia of such mixture combines with more or less of the carbon dioxid and water of thefisame to form carbonate of ammonia;

11 The process of making ammonium carbonate and free sulfur from gases eontaining ammonia, carbon dioxid and hythe said constituents from'said gases, sepia rating said carbon dioxid and hydrogen sulfid from said ammonia, mixing with the separated carbon dioxid and hydrogen sulfid equal to one-half the normal v0 ume of the hydrogen sulfid, contacting the said mixture with oxid of iron maintained at a red heat to form water and free sulfuncooling the gaseous mixture after the same has been, contacted with said iron oxid to condense sulfur, mixing the residual gases containing carbon dioxid and water with said separated mixture below 124 Fah. to form a carbonated salt of ammonia and separating said salt from residual gases. 12. The process of recovering "ammonium carbonate and free sulfur from crude gas which comprises contacting said crude gas with a liquor containing free ammonia, whereby the ammonia carbon dioxid and hydrogen sulfid contained in said crude gas are absorbed by said liquor,.withdrawing said liquor from contact with said crude gas, subjecting said liquor to'heatin whereby a major portion of the hydrogen sulfid and carbon dioxid and a minor portion liquor, subjecting a' portion {of the heated liquor to boiling-to separate therefrom substantially allofits yolatizable ammonia, oxidizing the hydrogen sulfid evolved in the heating of said liquor to form water and free sulfur, removing the so-formed .free sulfur from the residual gases, mixing the said residual gases v with the separated ammonia and cooling the resulting mixture, whereby'more or less of the carbon dioxid of said residual combines with the ammonia present to form commercial 'carbon-ate of ammonia.

13 The process of recovering ammonium carbonate and free sulfur from crude coal gaswhich comprises contacting said gas with a liquor containing free ammonia, whereby" the'ammonia and acid components of the crude gas are absorbed bysaid liquorto form foul liquor, withdrawing said foul liquor .from contact with said gas, subjecting said foul liquor to heating, whereby a major portion of the ammonium salts in said liquor are dissociated with the evolution from said liquor of the major portion of its hydrogen drogen sulfid, which comprises, separatingp bothof said streams, contacting the cooled with said second stream the unabsorbed gases evolved from said foul liquor, mixing oxygen with said unabsorbed gases in quantity sufficient to oxidize the hydrogen of; the hydrogen sulfid contained in said [unabsorbed gases, contacting the so formed gas mixture wtih a catalytic material capable of acting as a carrier. of the oxygen of said mixture tothe said hydrogen sulfid, .whereby the hydrogen of said hydrogen sulfid is oxidized to water and the sulfur of the same is set free, separating the sulfur set free-from the residual gases, mixing the said residual gases with the ammonia Separated from the minor portion of said purified liquor, and cooling thepmixture, whereby more or less of the'carbon dioxid and water of said residual gases is caused to unite with thesaid ammonia to form a carbonated salt of ammonia.

'14 The process of making sulfur and a carbonated salt of ammonium from crude c oal as which comprises contacting said gas with a purified ammoni'acal liquor containing free ammonia, whereby the major portion of theammonia, the carbon dioxid, the

said purified liquor hydrogen sulfid, and other impurities of the crudergas, are absorbed by said llquor to form f oul l1 uor WltlltlltHVllt" said foul liquor from contact with said gas, subjecting said foul liquor to heating by hot purified liquor. further heating said foul liquor at a temperature below the boiling point 01 said liquor at the pressure at which it is subjected, until a major portion of the ammonium salts of said liquor are dissociated with the elimination from said liquor of the major portion of its acid components and a minor proportioi-i of its ammonia to torn. purilied liquor, cooling the maJor portion of said purified liquor by a fresh portion ot'said foul liquor, and using the said cooled major portion of said purified liquor to scrub the major portion of the ammonia and of the hydrogen suliid from a fresh portion of crude gas, subjecting the minor portion of said purified liquor to boiling to distil oft substantially all of its volatilizable gases, withdrawing the distilled gases from contact with said liquor and removing from said gases the major part of their contained hydrogen sulfid and carbon dioxid whereby a relatively pur v an'nnonia is obtained, subjecting a fraction of the boiled minor portion of to boiling with lime, whereby substantially all of its ammonia is eliminated from said fraction, adding said ammonia to the gases distilled ofl' from the boiled minor portion of said purified liquor, cooling the remainderof the said boiled minor portion of said purified liquor, using the major portion of the cooled liquor to scrub the said crude gas after the latter has been scrubbed by said purified liquor, using the minor portion of said boiled and cooled purified liquor to absorb the ammonia from the gases eliminated in the heating of said i tuilliquor and mingling the said minor por-. tion of boiled and cooled purified liquor with a fresh portion of foul liquor mixing with'tlugasesevolved from the tool liquor after the ammonia has been removed from the same, enough air to supplv suflicient ox \=gen to oxidize the hyt'lrogeu of the hydrogen sulfid in said gases, contacting the resulting gas mixture with oxid of iron maintained below or at a red heat, wherehv the said h \;'drogen sulfid is converted to water and free sulfur; cooling the mixture of gases and sulfur apor to condense the said sulfur, and separating the condensed suliur from the residual gases, mixing said residual gases with the said relatively pure annnonia obtained by boiling the minor portion of said purified liquor and cooling the resulting mixture below 12 1 Falr, whereby the ammonia of said mixture combines with more or less of the carbon dioxidand water of said residual gases to form a earbonateo salt of aunnonia, and separating the soformed salt of ammonia from the residual gases of the mixture.

Signed at New York city, in the county of New York and State of New York, this 12th day of l ebruary, A. D. 1910.

HENRY L. DOHERTY. Witnesses L. G. COLEMAN, Tn0s..I. CARTER. 

